In the field of silver halide photographic light-sensitive materials, various techniques have heretofore been considered to improve covering power of silver halide in view of saving silver. As one of the techniques, it is known to use tabular silver halide grains.
This technique of using tabular silver halide grains is excellent with respect to improving covering power. However, light-sensitive materials using tabular silver halide grains are susceptible to changes in development processing conditions. Therefore, the results obtained with the use of such grains is still not completely satisfactory.
It has been known to incorporate various additives, such as stabilizers and antifoggants, in ordinary silver halide photographic light-sensitive materials for the purpose of improving their dependence on development processing conditions. For example, nitrobenzimidazoles, mercaptothiazoles, benzotriazoles, nitrobenzotriazoles, mercaptotetrazoles, etc. are described as such additives in U.S. Pat. Nos. 3,954,474 and 3,982,947, Japanese Patent Publication No. 28660/77, etc. However, these additives cannot depress fluctuation of gradation of a silver halide photographic light-sensitive material containing tabular grains which can be caused by change in Br.sup..crclbar. ion concentration of a developing solution or by high-temperature processing. However, these additives can depress an increase in fog of the light-sensitive material when processed in high-temperature processing.
For example, high-temperature development for efficiently conducting development, particularly, high-temperature, accelerated development processing using an automatic developing machine, is known and applied to processing of various light-sensitive materials with good results. However, since light-sensitive materials are to be processed at elevated temperatures in this type development processing, photographic emulsion films must be prevented from becoming physically fragile during the processing due to pressure applied thereto by rollers and belts of the automatic developing machine. Therefore, techniques must be worked out to enhance the physical strength of emulsion films with during their development in a developing solution to thereby maintain their physical strength. For this purpose, there is a technique of conducting processing with an aldehyde hardener to a developing solution. This technique serves to shorten the whole processing time due to the high-temperature processing, and the purpose of accelerating the processing can be attained to some extent. However, development processing with a developing solution containing, for example, an aldehyde, particularly an aliphatic dialdehyde, concurrently causes serious fog. This tendency becomes more serious as the temperature of the developing solution becomes higher and as the processing time becomes longer. The fog to be caused with such aldehydes can be depressed to some extent by using strong antifogging agents such as benzotriazole and 1-phenyl-5-mercaptotetrazole (described in PHOTOGRAPHIC PROCESSING CHEMISTRY written by L. F. A. Mason, p. 40). However, these antifogging agents concurrently have a strong effect on depressing development, thus emulsion sensitivity is seriously reduced. In spite of the addition of such strong antifogging agents, liquid compositions of a developing solution still undergo considerable change in the high-temperature, accelerated processing (for example, at 28.degree. to 38.degree. C. for 25 seconds) by air oxidation of the developing solution and by change of processed light-sensitive materials, resulting in serious fluctuation of photographic properties.
In addition, alkylene oxides, which can improve the dependence of the photographic properties on development processing conditions, cannot be added to ordinary silver halide photographic emulsions because they seriously decrease sensitivity.